Car Affordability Calculator

What this car affordability calculator does

Buying more car than you can afford is one of the most common money mistakes, and it is easy to make because dealers and lenders quote you a monthly payment, never the full cost of ownership. A low payment achieved by stretching a loan to 72 or 84 months feels affordable until you add insurance, fuel, maintenance, and the fact that the car is depreciating faster than you are paying it off. This calculator flips the question around. Instead of just telling you a payment, it tells you the maximum car price you can truly afford on your income, shows your all-in monthly cost as a percentage of gross income, and gives a plain-English verdict so you know instantly whether the car you are eyeing is affordable, a stretch, or a budget-buster. The result updates as you type.

The 20/4/10 rule (the backbone of this tool)

Financial planners use a simple, battle-tested guideline for car buying called the 20/4/10 rule:

• 20% down — put at least 20% of the price down so you are not immediately "underwater" (owing more than the car is worth).
• 4-year loan — finance for no more than 48 months. If you cannot afford the car over four years, you cannot really afford the car.
• 10% of income — keep your total monthly car costs (loan payment plus insurance, fuel, and maintenance) under 10% of your gross monthly income.

This calculator works the rule backwards: it takes 10% of your gross income, subtracts your running costs, and figures out the largest loan — and therefore the largest car price with 20% down — that still fits. That is the number competitors rarely give you.

How to use it

1. Annual gross income — your pay before tax. The rule is based on gross, not take-home.
2. Car price — the out-the-door price of the car you are considering.
3. Down payment / trade-in — cash plus the value of any vehicle you trade in.
4. APR and term — the interest rate the lender quotes and the loan length. Try setting the term to 4 years to test the rule.
5. Running costs — your monthly insurance, fuel, and a small allowance for maintenance and tyres. A common estimate is $120–$200/month.

How much car can you afford by income?

The table below applies the 20/4/10 rule (4-year loan at 7% APR, ~$150/month running costs) to show the rough maximum car price for different incomes. Your own number will shift with your rate and running costs — use the calculator for an exact figure.

Worked examples

Why total cost of ownership matters more than the payment

The sticker price and the loan payment are only part of what a car costs. Over a year you also pay for insurance (often $1,200–$2,500), fuel, registration, tyres, and routine maintenance, plus depreciation — the silent expense that can be the largest of all in the first few years. Stretching to an 84-month loan to "afford" a pricier car means you keep paying interest long after the car has lost much of its value, and you are more likely to owe more than it is worth if you need to sell. Keeping total monthly costs under 10% of gross income protects you from that trap and leaves room for the rest of your budget.

Tips to afford more car safely

• Increase your down payment. Every extra $1,000 down lowers the loan and the payment, and helps you hit the 20% target that keeps you above water.
• Shop the loan, not just the car. Get pre-approved by your bank or a credit union before visiting the dealer; their rate is your benchmark.
• Keep the term at 48 months or less. A shorter loan costs more per month but far less in total interest and builds equity faster.
• Buy slightly used. A 2–3 year old car skips the steepest depreciation, so your money buys more car for the same monthly cost.
• Get an insurance quote before you buy. Premiums vary hugely by model; a sportier car can blow your 10% budget on insurance alone.

Frequently asked questions